In previous infertility treatment, recently, it is necessary to evaluate the prospect of uterine receptivity in each menstrual cycle. Uterine receptivity has been clinically estimated via (1) measurement of blood progesterone level, (2) measurement of the uterine endometrial thickness using ultrasonic diagnostic equipment, and (3) histological examination of a physically collected uterine endometrium. However, among the methods (1) to (3), the method (3) is invasive for the patient, and is unreliable for predicting the outcome of infertility treatment, and thus, remains to be controversial in clinical significance. Although methods (1) and (2) have been used in daily practice, they are not effective enough to evaluate the prospect of uterine receptivity.
Using human implantation failure model mice established by the Inventors (Nakamura, et al.) (Non patent literature 1), the Inventors found that the following three parameters could evaluate the prospect of uterine receptivity (Patent literature 1);
a redox potential difference, a uterine endometrial impedance, and an intravaginal impedance were effective parameters. For this purpose Patent literature 1 discloses the general shape of a device which can contact with the vaginal wall and a device which can make contact with the uterine wall and be inserted into uterine cavity to measure a uterine endometrial impedance or a uterine endometrial redox potential difference in real time to evaluate the prospect of uterine receptivity.
As described in Patent literature 1, to evaluate the uterine implantation capacity, it is important to measure the redox potential difference and the impedance and further, it is necessary to measure them accurately. As disclosed in Patent literature 1, to evaluate the prospect of uterine receptivity, these devices preferably have to be particular shapes to keep the electrodes in contact with the uterine wall or the vaginal wall and also to be inserted into the vagina or uterine cavity. However, Patent literature 1 did not mention the specific shape of the probe and arrangement of the electrodes and Patent literature 1 did not provide a method for how to keep the electrodes in contact with accurately with vaginal or uterine wall and a method of reducing the burden on the patient, which is important in the field of infertility treatment.
Consequently, in the field of infertility treatment, there is a demand for a medical equipment to evaluate the prospect of uterine receptivity vagina evaluation device or a uterus evaluation device that has specific shapes of vaginal and uterine probes with specific arrangement of electrodes which can accurately measure a uterine endometrial redox potential difference or uterine endometrial impedance in the uterine cavity, or a uterine endometrial impedance on the vagina wall, and can reduce the burden on the patient at the point of insertion of the probe into the vagina or the uterine cavity (accurate measurement and low invasiveness to the patients are highly demanded).